Wong Donny I M, Dockerty John D
Department of Preventive and Social Medicine, University of Otago, Dunedin, New Zealand.
BMC Blood Disord. 2006 Sep 14;6:5. doi: 10.1186/1471-2326-6-5.
Some studies have found that lower parity and higher or lower social class (depending on the study) are associated with increased risks of childhood acute lymphoblastic leukaemia (ALL). Such findings have led to suggestions that infection could play a role in the causation of this disease. An earlier New Zealand study found a protective effect of parental marriage on the risk of childhood ALL, and studies elsewhere have reported increased risks in relation to older parental ages. This study aimed to assess whether lower parity, lower social class, unmarried status and older parental ages increase the risk of childhood ALL (primarily). These variables were also assessed in relation to the risks of childhood acute non-lymphoblastic leukaemia, non-Hodgkin's lymphomas and Hodgkin's disease.
A case control study was conducted. The cases were 585 children diagnosed with leukaemias or lymphomas throughout New Zealand over a 12 year period. The 585 age and sex matched controls were selected at random from birth records. Birth records from cases (via cancer registration record linkage) and from controls provided accurate data on maternal parity, social class derived from paternal occupation, maternal marital status, ages of both parents, and urban status based on the address on the birth certificate. Analysis was by conditional logistic regression.
There were no statistically significant associations overall between childhood ALL and parity of the mother, social class, unmarried maternal status, increasing parental ages (continuous analysis), or urban status. We also found no statistically significant associations between the risks of childhood acute non-lymphoblastic leukaemia, non-Hodgkin lymphomas, or Hodgkin's disease and the variables studied.
This study showed no positive results though of reasonable size, and its record linkage design minimised bias. Descriptive studies (eg of time trends of ALL) show that environmental factors must be important for some diagnoses. Work has been done on the risk of ALL in relation to chemicals (eg pesticides) and drugs, dietary factors (eg vitamins), electromagnetic fields and infectious hypotheses (to name some); but whether these or other unknown factors are truly important remains to be seen.
一些研究发现，低生育次数以及较高或较低的社会阶层（取决于具体研究）与儿童急性淋巴细胞白血病（ALL）风险增加有关。这些发现促使人们认为感染可能在该疾病的病因中起作用。新西兰早期的一项研究发现父母婚姻对儿童ALL风险具有保护作用，而其他地方的研究报告称父母年龄较大时风险增加。本研究旨在评估低生育次数、低社会阶层、未婚状态和父母年龄较大是否会增加儿童ALL（主要是）的风险。还评估了这些变量与儿童急性非淋巴细胞白血病、非霍奇金淋巴瘤和霍奇金病风险的关系。
进行了一项病例对照研究。病例为在12年期间新西兰各地诊断出患有白血病或淋巴瘤的585名儿童。从出生记录中随机选择585名年龄和性别匹配的对照。病例（通过癌症登记记录链接）和对照的出生记录提供了关于母亲生育次数、根据父亲职业得出的社会阶层、母亲婚姻状况、父母双方年龄以及基于出生证明上地址的城市状况的准确数据。采用条件逻辑回归进行分析。
总体而言，儿童ALL与母亲生育次数、社会阶层、母亲未婚状态、父母年龄增加（连续分析）或城市状况之间没有统计学上的显著关联。我们还发现儿童急性非淋巴细胞白血病、非霍奇金淋巴瘤或霍奇金病的风险与所研究的变量之间没有统计学上的显著关联。
本研究虽规模合理但未得出阳性结果，其记录链接设计将偏差降至最低。描述性研究（例如ALL的时间趋势研究）表明，环境因素对于某些诊断肯定很重要。已经针对ALL与化学物质（例如农药）和药物、饮食因素（例如维生素）、电磁场以及感染假说（仅举几例）的风险开展了研究；但这些因素或其他未知因素是否真正重要仍有待观察。
